帮会粮票：票据面额的档位兑换

local function grantTicket(actor, n)
    setplayvar(actor, "grainTicket",
        (getplayvar(actor, "grainTicket") or 0) + n)
    sendmsg(actor, 1, "粮票 +" .. n)
end
local function exchange(actor, tier)
    local COST = {5, 12, 30}
    local have = getplayvar(actor, "grainTicket") or 0
    if have < COST[tier] then
        sendmsg(actor, 1, "粮票不足，需 " .. COST[tier])
        return
    end
    setplayvar(actor, "grainTicket", have - COST[tier])
    giveitem(actor, 8900 + tier, 1)
    sendmsg(actor, 1, "兑换 " .. tier .. " 档物资")
end

local function queryTicket(actor)
    sendmsg(actor, 1, "持有粮票 "
        .. (getplayvar(actor, "grainTicket") or 0)
        .. " 张，月底过期")
end